Iran has carried out 40 executions since the start of 2014, according to Amnesty International, with at least 33 taking place in the last week.

The human-rights organization released a statement Thursday detailing 21 executions acknowledged by Iranian officials, and another 19 that were “reported through reliable sources.” Public hangings in Iran are typically a show of force: a crane is used to lift the person by a noose tied around their neck in front of a crowd.

“The spike in the number of executions carried out so far this month in Iran is alarming,” said Hassiba Hadj Sahraoui, Amnesty’s deputy director for the Middle East and North Africa. “The Iranian authorities’ attempts to change their international image are meaningless if at the same time executions continue to increase.”

Alleged drug offenses are thought to be the root cause of most of Iran’s executions, but Amnesty says those types of non-lethal crimes don’t warrant the death penalty. The group called on Iran to end the practice and reform its Revolutionary Court trials, frequently held behind closed doors.